JP4621044B2 - Load distribution apparatus and load distribution method - Google Patents

Description

  The present invention relates to a load distribution apparatus and a load distribution method for performing load distribution of multicast data transfer processing, and in particular, can perform load distribution of multicast data transfer processing without imposing a burden on a router, and can perform high-speed transfer. The present invention relates to a load distribution apparatus and a load distribution method capable of performing a start operation.

  In a network using TCP / IP (Transmission Control Protocol / Internet Protocol), when it is necessary to transmit the same information to a large number of terminals all at once, multicast is often used. Specifically, multicast is used for video distribution over the Internet.

  In communication by unicast, when the same data is transmitted to a plurality of terminals, it is necessary to generate packets having the same contents as the number of terminals, and to transmit by specifying the IP address of each terminal. In communication using multicast, one packet can be transmitted to a plurality of terminals by designating an address assigned as a multicast address. For this reason, in communication using multicast, the load on the network can be reduced.

  When performing communication by multicast across a plurality of networks, it is necessary to perform route control using a protocol called a multicast routing protocol. PIM-SM (Protocol Independent Multicast-Sparse Mode), which is a typical multicast routing protocol, can efficiently construct a communication path called a multicast tree using a Join / Prune message.

  A router (relay device) that uses PIM-SM periodically transmits a survival confirmation message to notify the routers in the neighboring network of its existence. This existence confirmation message also has a role of preventing duplicate transfer of multicast data. When a plurality of routers are connected to a LAN (Local Area Network), if each router relays multicast data, a plurality of the same packets may be transmitted on the LAN. To prevent this, when the existence confirmation message is received and the existence of another router on the same LAN is confirmed, only the router having the largest IP address becomes the DR (Designated Router) and takes charge of relaying multicast data. It is a mechanism.

  As described above, only the DR relays multicast data, so that it is possible to prevent duplicate transfer of multicast data. However, when a large amount of multicast data needs to be processed, the load on the DR becomes very high. End up. In order to solve this problem, Patent Document 1 uses VRRP (Virtual Router Redundancy Protocol) to operate a plurality of routers virtually as a single router and to exclusively set a multicast address for transfer processing. A technique for extending to exchange messages is disclosed. If this technology is used, each router will perform the transfer processing of the data of the multicast address allocated to itself, and load distribution is implement | achieved.

JP 2003-23444 A

  However, when using the technique of Patent Document 1, the router must operate VRRP in addition to a normal protocol for multicast such as PIM-SM, and the load increases accordingly. In addition, since the multicast address to be transferred is determined by exchanging messages between routers, the message exchange becomes an overhead, and a high-speed transfer start operation cannot be performed.

  The present invention has been made to solve the above-described problems caused by the prior art, and can realize load distribution of multicast data transfer processing without imposing a burden on the router, and can perform a high-speed transfer start operation. An object of the present invention is to provide a load distribution apparatus and a load distribution method that can be performed.

  In order to solve the above-described problems and achieve the object, the present invention provides a load balancer connected to a plurality of routers that perform multicast data transfer processing, and a packet identification unit that identifies a type of a received packet; A message distribution unit that distributes the packet identified by the packet identification unit as a participation message or a leaving message exclusively to the router based on a distribution rule stored in the storage unit.

  The present invention is also a load distribution method for controlling a plurality of routers that perform multicast data transfer processing, wherein the packet identification step identifies the type of received packet, and the packet identification step includes a join message or a leave message. And a message distribution step of exclusively distributing the identified packet to the router based on the distribution rule stored in the storage means.

  According to the present invention, since the participation message and the leaving message from the terminal are distributed to the router based on the route distribution rule, the load distribution of the transfer process can be realized without imposing a burden on each router. . In addition, since it is not necessary to exchange messages between routers for load distribution, a high-speed transfer start operation can be performed.

  Further, the present invention is characterized in that, in the above invention, further provided is a survival confirmation message discarding means for discarding the packet identified by the packet identification means as the survival confirmation message.

  According to the present invention, since the existence confirmation message transmitted from the router is discarded before other routers receive it, all the routers receive multicast data when multiple routers are connected to the LAN. It is possible to make a state of performing the transfer.

  Also, the present invention is characterized in that, in the above-mentioned invention, the message distribution means dynamically adds the distribution rule in consideration of equalizing the load on the router.

  According to the present invention, the load situation is judged and the route distribution rule is dynamically registered, so that the load of each router can be equalized.

  The present invention further includes failure detection means for detecting a router failure in the above invention, wherein the message distribution means uses the router as a distribution destination when the failure detection means detects a router failure. The distribution rule is updated, and the distribution destination is replaced with another router.

  According to the present invention, when a router abnormality is detected, the distribution rule that is the distribution destination of the router is configured to be updated with another router as the distribution destination. In some cases, the forwarding process can be taken over by the router.

  According to the present invention, since the participation message and the leaving message from the terminal are distributed to the router based on the route distribution rule, it is possible to realize the load distribution of the transfer process without imposing a burden on each router. There is an effect. In addition, since it is not necessary to exchange messages between routers for load distribution, there is an effect that a high-speed transfer start operation can be performed.

  In addition, according to the present invention, since the existence confirmation message transmitted from the router is discarded before other routers receive the message, all routers are connected when a plurality of routers are connected to the LAN. There is an effect that multicast data can be transferred.

  In addition, according to the present invention, the configuration is such that the route distribution rule is dynamically registered by judging the load situation, so that the load of each router can be equalized.

  In addition, according to the present invention, when a router abnormality is detected, the distribution rule for which the router is a distribution destination is updated so that another router is the distribution destination. If this occurs, the router can take over the transfer process.

Exemplary embodiments of a load distribution apparatus and a load distribution method according to the present invention will be explained below in detail with reference to the accompanying drawings. Hereinafter, first, a multicast mechanism will be briefly described, and then a load distribution device and a load distribution method according to the present invention will be described.
(Multicast mechanism)

  First, the multicast mechanism will be briefly described. FIG. 25 is a sample diagram showing an example of a network configuration when performing multicast. A server 1000 that transmits data is connected to the Internet 100 via a router 2001. Terminals 3001 to 3003 that receive data are connected to the LAN 200. The LAN 200 is connected to the Internet 100 via the router 2002.

  In order to transmit data from the server 1000 to the terminals 3001 to 3003 by multicast, it is necessary to perform a predetermined procedure between the router 2001 and the router 2002 and between the router 2002 and the terminals 3001 to 3003. Here, a procedure between the router 2002 and the terminal 3001 will be described. FIG. 26 is a sequence diagram showing a communication procedure when multicasting is performed.

  The router 2002 multicasts a participation inquiry message for inquiring whether there is a terminal receiving the multicast on the LAN 200. A terminal that receives data of the same multicast address is called a multicast group, but this participation inquiry message is transmitted at a fixed time interval without specifying the multicast group. The terminal 3001 that has received the participation inquiry message multicasts a participation message that is addressed to the received multicast address. Then, the router 2002 that has received the participation message starts transferring data of the designated multicast address.

  When the multicast reception ends, the terminal 3001 multicasts the leave message. The router 2002 that has received the leave message multicasts a join inquiry message that designates the multicast group in order to confirm whether or not the multicast group that receives the data of the multicast address designated by the leave message remains on the LAN 200. To do. If the participation message is not responded for a certain period, the transmission of the data of the multicast address is stopped.

  Here, consider a case where the LAN 200 is connected to a plurality of routers. If a plurality of routers respectively perform multicast relay, the same data may be transmitted over the LAN 200 in duplicate. In order to prevent this, when a plurality of routers are connected to the LAN, only one router performs a multicast relay. FIG. 27 is an explanatory diagram for explaining the operation when there are a plurality of routers.

  This figure shows an example in which two routers, routers 2002 and 2003, are connected to the LAN 200. Each of the routers 2002 and 2003 multicasts a survival confirmation message at regular time intervals. Then, only the router having the largest IP address (in the example of FIG. 27, the router 2002 has a larger address) becomes the DR and performs multicast relay.

  In this way, since only one router becomes the DR and takes charge of relaying multicast data, the same data is not repeatedly transmitted on the LAN 200. However, when a large amount of multicast data needs to be relayed, the load is concentrated on the router 2002 that has become the DR, and the processing capability of the router 2003 is not effectively utilized.

  First, the principle of the load distribution method according to the present embodiment will be described. FIG. 1 is an explanatory diagram for explaining the principle of the load distribution method according to the present embodiment. As shown in the figure, in the load distribution method according to the present embodiment, a load distribution device 4000 is provided between the router 2002 and the router 2003, and the load distribution device 4000 and the LAN 200 are connected.

  The load balancer 4000 includes a survival confirmation message blocking function and a participation / leaving message distribution function. The existence confirmation message blocking function is a function for blocking the existence confirmation message sent by the router 2002 and the router 2003 so that other routers do not receive the message. By blocking the existence confirmation message, only one router is prevented from becoming a DR, and both the router 2002 and the router 2003 perform a multicast data transfer process.

  The participation / leaving message distribution function is a function for distributing the participation message and the leaving message transmitted by the terminals 3001 to 3003 to either the router 2002 or the router 2003 based on a predetermined rule. By distributing the participation message and the leaving message, the sharing of the multicast address to be transferred is determined, and the load distribution of the transfer process is realized. When realizing the load distribution, the router does not need to perform any special processing, so the router is not burdened.

  Further, since it is not necessary to exchange messages between routers for load distribution, high-speed operation becomes possible. In addition, since the load distribution device 4000 distributes the participation message and the leaving message, the router 2002 and the router 2003 do not receive the joining message and the leaving message that are not related to the router 2002 and the router 2003, so that the load can be reduced. is there.

  For example, when the terminal 3001 transmits a participation message for receiving data of the multicast address A and the participation / leaving message distribution function distributes this message to the router 2002, the router 2002 is in charge of transferring the data of this multicast address. To do. In this case, even if the terminal 3002 or the terminal 3003 transmits a participation message for receiving the data of the multicast address A, the message is distributed according to the same rule, and the message is distributed to the router 2002. Therefore, the router 2003 transmits the same multicast data. There is no transfer to the LAN 200.

  In addition, when any of the terminals 3001 to 3003 transmits a leave message for stopping the reception of the multicast address A, the same rule is assigned and the message is assigned to the router 2002, so that the leave message is also appropriately processed. The In this way, the distribution of the participation message and the leaving message is performed exclusively in the load balancer 4000, and it is not necessary to apply special expansion to each router device.

  Next, the configuration of the load distribution apparatus according to the present embodiment will be described. FIG. 2 is a functional block diagram illustrating the configuration of the load distribution apparatus according to the present embodiment. As shown in the figure, the load balancer 4000a includes a network interface unit 4100a, a packet identification unit 4200a, a survival confirmation message discard unit 4300a, a join / leave message distribution unit 4400a, and a packet transfer unit 4500a.

  The network interface unit 4100a is an interface unit for exchanging packets through the network. The network interface unit 4100a has a plurality of ports for connecting to a router and a port for connecting to a LAN. Note that a plurality of ports for connecting to the router do not necessarily have to be physically present, and may be virtually divided into a plurality of ports by a VLAN (Virtual LAN) or the like.

  The packet identification unit 4200a is a processing unit that identifies the type of packet received by the network interface unit 4100a and delivers it to the processing unit according to the type. Specifically, if the received packet is a survival confirmation message, it is delivered to the survival confirmation message discarding unit 4300a. If it is a participation message or a withdrawal message, it is delivered to the participation / leaving message distribution unit 4400a. Hand over to part 4500a.

  FIG. 3 is a functional block diagram showing the configuration of the packet identification unit 4200a. As shown in the figure, the packet identification unit 4200a includes a header extraction unit 4210a, an identification rule search unit 4220a, and an identification rule storage unit 4230a. The header extraction unit 4210a is a processing unit that extracts information necessary for identifying the type from the header part of the packet. The identification rule search unit 4220a is a processing unit that searches for an identification rule stored in the identification rule storage unit 4230a using the information extracted by the header extraction unit 4210a as a key, and determines a distribution destination.

  The identification rule storage unit 4230a is a storage unit that stores identification rules for packet identification and distribution. FIG. 4 is a sample diagram illustrating an example of an identification rule. As shown in the figure, the packet type is identified based on the destination MAC (Media Access Control) address, the destination IP address, and the value of the TYPE field of the payload portion. For example, a packet in which the destination MAC address is 01-00-5E-00-00-02, the destination IP address is 224.0.0.2, and the value of the TYPE field in the payload portion is 0x17 is a leave message. It is identified as a type, and is distributed to the participation / leaving message distribution unit 4400a.

  The survival confirmation message discarding unit 4300a is a treatment unit that discards the survival confirmation message without transferring it. When the existence confirmation message discarding unit 4300a discards the existence confirmation message, the existence confirmation message is not received by the router, so that only one router does not become the DR, and all routers transfer multicast data. It will be in a state that can be.

  The join / leave message distribution unit 4400a is a processing unit that determines to which router device the join message and the leave message are distributed based on a predetermined rule. There are several methods for distributing the join message and the leave message. In this embodiment, the distribution is performed based on a static table in which a distribution destination is defined for each multicast address.

  FIG. 5 is a functional block diagram showing the configuration of the join / leave message sorting unit 4400a. As shown in the drawing, the participation / leaving message distribution unit 4400a includes a header extraction unit 4410a, a route distribution rule search unit 4420a, and a route distribution rule storage unit 4430a. The header extraction unit 4410a is a processing unit that extracts information necessary for determining the distribution destination from the header of the packet. The route distribution rule search unit 4420a is a processing unit that searches for a route distribution rule stored in the route distribution rule storage unit 4430a using the information extracted by the header extraction unit 4410a as a key, and determines a distribution destination.

  The route distribution rule storage unit 4430a is a storage unit that stores a route distribution rule for packet distribution. FIG. 6 is a sample diagram showing an example of a route distribution rule. As shown in the figure, the route distribution rule in this embodiment holds a multicast address and an output route of a packet having the multicast address as a pair. For example, a packet having the multicast address A is output from port 1 of the network interface unit 4100a.

  This route distribution rule is a static rule set in advance by an administrator or the like. The multicast address may be an IP address or a MAC address. The output route may be a physical port or a logical port such as a VLAN.

  The packet transfer unit 4500a is a processing unit that transfers a packet delivered from the packet identification unit 4200a and the join / leave message distribution unit 4400a via the network interface unit 4100a. The packet delivered from the participation / leaving message sorting unit 4400a is transferred only to the port designated by the joining / leaving message sorting unit 4400a.

  Next, the processing procedure of the load balancer 4000a will be described. FIG. 7 is a flowchart showing the processing procedure of the load balancer 4000a. As shown in the figure, when receiving the packet (step S1001), the load balancer 4000a identifies the type of packet in the packet identification unit 4200a (step S1002). If the packet is a survival confirmation message (Yes at step S1003), the survival confirmation message discarding unit 4300a discards the packet (step S1004).

  If the packet is not a survival confirmation message (No at Step S1003), but is a participation message or a leaving message (Yes at Step S1005), a forwarding destination determination process (to be described later) is performed in the joining / leaving message distribution unit 4400a to which router to transfer. (Step S1006) and transfer is performed from the packet transfer unit 4500a (step S1007). If the packet is neither a join message nor a leave message (No at step S1005), the packet is transferred directly from the packet transfer unit 4500a (step S1007).

  Next, the processing procedure of the transfer destination determination process will be described. FIG. 8 is a flowchart illustrating the processing procedure of the transfer destination determination process. As shown in the figure, when the participation / leaving message distribution unit 4400a acquires the multicast address from the packet (step S1101), it searches for the route distribution rule stored in the route distribution rule storage unit 4430a, Information on the transfer destination is acquired and designated as the transfer destination in the packet transfer unit 4500a (step S1102).

  As described above, in the first embodiment, the load balancer 4000a is provided between the routers, and the survival confirmation message discarding unit discards the survival confirmation message. Therefore, a plurality of routers are connected to the LAN. In this case, all routers can be in a state of forwarding multicast data.

  Further, in the first embodiment, the configuration is made such that the participation message and the leaving message from the terminal are distributed to the router based on the route distribution rule in which the forwarding destination is defined for each multicast address, so that there is no burden on each router. The load distribution of the transfer process can be realized, and a high-speed transfer start operation can be obtained.

  In this embodiment, the survival confirmation message is blocked by the survival confirmation message discarding unit 4300a. However, it can also be realized by using layer 2 switch filtering. In this case, the load balancer 4000a need not include the survival confirmation message discarding unit 4300a.

  In the first embodiment, the case where the route distribution rule is set based on the multicast address has been described. However, in this case, since it is necessary to set rules for all multicast addresses that can be processed, a burden is placed on the administrator who sets the route distribution rules. Further, it is not possible to process a join message and a leave message of a multicast address that are not set in the rule. Therefore, in the second embodiment, a case will be described in which a multicast address is arithmetically processed and distribution is performed based on the arithmetic result.

  First, the configuration of the load distribution apparatus according to the present embodiment will be described. The configuration of the load balancer according to the present embodiment is obtained by replacing the join / leave message distribution unit 4400a of the load balancer 4000a described in the first embodiment with a join / leave message distribution unit 4400b. FIG. 9 is a functional block diagram showing the configuration of the join / leave message sorting unit 4400b.

  As shown in the figure, the participation / leaving message distribution unit 4400b includes a header extraction unit 4410b, a route distribution rule search unit 4420b, a route distribution rule storage unit 4430b, and a header information calculation unit 4440b. The header extraction unit 4410b is a processing unit that extracts address information such as a multicast address from the header part of the packet. The header information calculation unit 4440b is a processing unit that digitizes the information extracted by the header extraction unit 4410b by hash calculation or the like.

  The route distribution rule search unit 4420b searches the route distribution rule stored in the route distribution rule storage unit 4430b based on the value obtained by the header information calculation unit 4440b, and determines a distribution destination. It is.

  The route distribution rule storage unit 4430b is a storage unit that stores a route distribution rule for packet distribution. FIG. 10 is a sample diagram showing an example of a route distribution rule. As shown in the figure, the route distribution rule in this embodiment holds the calculated value of the header information calculation unit 4440b and the output route of the packet from which the calculated value is calculated as a pair. For example, a packet whose calculated value is 0 is output from port 1.

  Since the route distribution rule according to the present embodiment is numerically expressed without directly using the multicast address, it is not necessary to set a rule for every multicast address by appropriately performing numerical conversion.

  Next, a processing procedure of the load distribution apparatus according to the present embodiment will be described. The processing procedure is the same as that of the first embodiment except that the processing procedure of the transfer destination determination process is different. Here, the processing procedure of the transfer destination determination process will be described. FIG. 11 is a flowchart illustrating a processing procedure of the transfer destination determination process. As shown in the figure, when the join / leave message allocating unit 4400b obtains a multicast address from the packet (step S2001), it calculates this (step S2002). Then, the route distribution rule stored in the route distribution rule storage unit 4430b is searched using the calculated value obtained in this calculation process as a key, transfer destination information is acquired, and this is designated as the transfer destination ( Step S2003).

  As described above, in the second embodiment, the multicast address included in the join message and the leave message from the terminal is digitized, and the distribution destination is determined based on the digitized value. The distribution process can be realized without setting the multicast address in the rule.

  In the first embodiment, the case where the participation message and the leaving message are distributed based on the route distribution rule defined in advance has been described. However, if distribution is performed based on the rules defined in advance as described above, the distribution destination may be biased to one router, and load distribution may not be performed appropriately. Therefore, in the third embodiment, an example in which route distribution rules are dynamically set and load distribution is performed equally will be described.

  First, the configuration of the load distribution apparatus according to the present embodiment will be described. The configuration of the load distribution apparatus according to this embodiment is obtained by replacing the participation / leave message distribution unit 4400a of the load distribution apparatus 4000a described in Embodiment 1 with a participation / leave message distribution unit 4400c. FIG. 12 is a functional block diagram showing the configuration of the join / leave message sorting unit 4400c.

  As shown in the figure, the participation / leaving message sorting unit 4400c includes a header extracting unit 4410c, a joining message processing unit 4421c, a leaving message processing unit 4422c, a timer 4423c, a route sorting rule storage unit 4430c, A road-specific entry number storage unit 4431c and a type determination unit 4450c are included. The header extraction unit 4410c is a processing unit that extracts information for determining the type of packet from the header part of the packet.

  The type determination unit 4450c determines whether the packet is a participation message or a leave message based on the information extracted by the header extraction unit 4410c. If the former, the type determination unit 4450c delivers the packet to the participation message processing unit 4421c. If it is the latter, it is a processing part handed over to the leaving message processing part 4422c. The packet type can be determined based on the same rule as the identification rule shown in FIG.

  The participation message processing unit 4421c is a processing unit that determines the distribution destination of the packet delivered from the type determination unit 4450c with reference to the route distribution rule stored in the route distribution rule storage unit 4430c. When the rule for distributing the packet is not stored in the route distribution rule storage unit 4430c, the participation message processing unit 4421c stores the number of entry information by route stored in the route entry number storage unit 4431c. , It is determined which route is the most vacant, and a rule for allocating the packet to the most vacant route is added to the route allocation rule storage unit 4430c to store the number of entries per route. The number-of-entry-specific entry number information stored in the unit 4431c is updated.

  In this way, the participation message processing unit 4421c determines the load status and dynamically registers the route distribution rule, so that the load distribution of each router is evenly performed. In addition, since the route distribution rule is registered without human intervention, the burden on the administrator is reduced.

  The leaving message processing unit 4422c is a processing unit that determines a distribution destination of the packet delivered from the type determination unit 4450c with reference to a route distribution rule stored in the route distribution rule storage unit 4430c. Further, the leaving message processing unit 4422c sets a flag indicating that the leaving message has been received in the rule used for distribution. This flag is cleared when the participation message processing unit 4421c distributes the participation message using the rule. If the flag is not cleared after a certain period of time, the leaving message processing unit 4422c considers that the rule is not already used, deletes it, and stores it in the route-specific entry number storage unit 4431c. Update the number of entries per route.

  In this way, the rule that the leave message processing unit 4422c is not used is deleted, and the effective load status is maintained in the route-specific entry number information, so that the load distribution of each router is kept even. Will be.

  The timer 4423c is a timer for detecting that the flag set in the route distribution rule by the leaving message processing unit 4422c is not cleared for a certain period of time. The route distribution rule storage unit 4430c is a storage unit that stores a route distribution rule for packet distribution. FIG. 13 is a sample diagram showing an example of a route distribution rule. As shown in the figure, the route distribution rule in this embodiment holds a multicast address and an output route of a packet having the multicast address as a pair, and further indicates a flag indicating that a leave message has been received. Can be held.

  The route entry number storage unit 4431c is a storage unit that stores route entry number information indicating the load state of each router. FIG. 14 is a sample diagram showing an example of route-specific entry number information. As shown in the figure, the route-specific entry number information holds a value obtained by tabulating the number of route distribution rule entries for each output port. For example, the data in the first row indicates that there are two entries for the rule assigned to port 1, which means that there are two multicast addresses assigned to the router corresponding to port 1.

  Next, a processing procedure of the load distribution apparatus according to the present embodiment will be described. The processing procedure is the same as that of the first embodiment except that the processing procedure of the transfer destination determination process is different. Here, the processing procedure of the transfer destination determination process will be described. 15 to 16 are flowcharts illustrating the processing procedure of the transfer destination determination process. As shown in the figure, the participation / leaving message distribution unit 4400c first determines the packet type in the type determination unit 4450c (step S3001).

  If the packet is a participation message (Yes at step S3002), the participation message processing unit 4421c searches for a route distribution rule, and acquires transfer destination information (step S3003). If a rule that matches the packet can be acquired (Yes at step S3004), the transfer destination defined in the acquired rule is adopted, and the flag of the rule is set to 0.

  If a rule that matches the packet could not be acquired (No at step S3004), the number-of-entry-specific entry number information is searched to acquire the path with the smallest number of entries (step S3006), and the acquired path is set as the transfer destination Adopt (step S3007). Then, a rule for allocating to this route is added to the route distribution rule (step S3008), and the number of entries in this route in the route-specific entry number information is added by 1 (step S3009).

  If it is determined in step S3001 that the packet is not a join message but a leave message (No in step S3002), the leave message processing unit 4422c searches for a route distribution rule and adopts the transfer destination defined in the acquired rule. (Step S3101). Then, the flag of the rule is set to 1 (step S3102), the timer is reset, and time measurement is started (step S3103).

  If the timer has timed out and the flag remains 1 (Yes at step S3201), the rule is deleted from the route distribution rule (step S3202), and the output method of this rule in the route-specific entry number information. The number of road entries is decremented by 1 (step S3203). If the flag has been reset to 0 when timed out (No at step S3201), no particular processing is performed.

  As described above, in the third embodiment, the route distribution rule is dynamically set in consideration of the large amount of distribution, so that the load distribution of the router can be equalized.

  In the third embodiment, an example has been described in which load distribution is equalized by aligning the number of distribution rule entries, that is, the number of multicast addresses in charge of distribution, but this method is not effective when considering the load of the entire network. May be appropriate. When there are a plurality of routes from the server that transmits the multicast data, it is appropriate to leave the transfer to the router connected to the route that is the shortest route or the router that is connected to the route with the widest bandwidth.

  The route that is the shortest route and the route that has the widest bandwidth can be acquired by referring to, for example, unicast routing information. Since it is necessary to refer to the unicast routing information based on the server IP address, it is convenient that the route distribution rule is based on the server IP address. In the fourth embodiment, an example in which the route distribution rule is based on the IP address of the server will be described.

  First, the configuration of the load distribution apparatus according to the present embodiment will be described. The configuration of the load balancer according to the present embodiment is obtained by replacing the join / leave message distribution unit 4400a of the load balancer 4000a described in the first embodiment with a join / leave message distribution unit 4400d. FIG. 17 is a functional block diagram showing the configuration of the join / leave message sorting unit 4400d.

  As shown in the figure, the participation / leaving message distribution unit 4400d includes a transmission source address extraction unit 4410d, a route distribution rule search unit 4420d, and a route distribution rule storage unit 4430d. The transmission source address extraction unit 4410d is a processing unit that extracts the IP address of the server that is the transmission source of the multicast data from the header portion of the packet.

  The route distribution rule search unit 4420d searches for a route distribution rule stored in the route distribution rule storage unit 4430d using the IP address acquired by the transmission source address extraction unit 4410d as a key, and determines a distribution destination It is.

  The route distribution rule storage unit 4430d is a storage unit that stores a route distribution rule for packet distribution. FIG. 18 is a sample diagram showing an example of a route distribution rule. As shown in the figure, the route distribution rule in the present embodiment holds the IP address of the transmission source server and the output route in pairs. This information may be automatically generated from the routing information, or may be set manually by the administrator. Further, instead of the IP address of the transmission source server, the network address and subnet mask to which the transmission source server belongs may be held.

  Next, a processing procedure of the load distribution apparatus according to the present embodiment will be described. The processing procedure is the same as that of the first embodiment except that the processing procedure of the transfer destination determination process is different. Here, the processing procedure of the transfer destination determination process will be described. FIG. 19 is a flowchart illustrating a processing procedure of transfer destination determination processing. As shown in the figure, when the join / leave message sorting unit 4400d acquires the IP address of the server that sent the data from the packet (step S4001), the join / leave message sorting unit 4400d stores it in the route sorting rule storage unit 4430d using this as a key. The stored route distribution rule is searched, transfer destination information is acquired, and this is designated as the transfer destination (step S4002).

  As described above, in the fourth embodiment, since the route distribution rule is set based on the IP address of the data transmission source, the unicast routing information and the route distribution rule are linked to each other. Multicast data can be transferred through an optimum route.

  When multiple routers are connected to the LAN, not only do load distribution to these routers, but even if some routers or routes fail, other routers take over the forwarding of multicast data Can also be made redundant. In the fifth embodiment, an example of realizing redundancy against a failure will be described. In addition, the method of implement | achieving load distribution may use any of Examples 1-4.

  First, the configuration of the load distribution apparatus according to the present embodiment will be described. FIG. 20 is a functional block diagram illustrating the configuration of the load distribution apparatus according to the present embodiment. As shown in the figure, the load balancer 4000e includes a network interface unit 4100e, a packet identification unit 4200e, a survival confirmation message discard unit 4300e, a join / leave message distribution unit 4400e, a packet transfer unit 4500e, and a failure detection unit. Unit 4600e and participation message generation unit 4700e.

  The network interface unit 4100e is an interface unit for exchanging packets through the network. The network interface unit 4100e has a plurality of ports for connecting to the router and a port for connecting to the LAN. Note that a plurality of ports for connecting to the router do not necessarily have to be physically present, and may be virtually divided into a plurality of ports by a VLAN or the like.

  The packet identification unit 4200e is a processing unit that identifies the type of packet received by the network interface unit 4100e and delivers it to the processing unit according to the type. Specifically, if the received packet is a survival confirmation message, it is delivered to the survival confirmation message discarding unit 4300e, if it is a participation message or a leaving message, it is delivered to the joining / leaving message sorting unit 4400e, and if it is any other packet, packet transfer is performed. Hand over to part 4500e. If the received packet is a survival confirmation message, the packet is also delivered to the failure detection unit 4600e.

  The survival confirmation message discarding unit 4300e is a treatment unit that discards the survival confirmation message without transferring it. The participation / leaving message sorting unit 4400e is a processing unit that determines which router device is to sort the joining message and the leaving message based on a route sorting rule. In addition, when the failure detection unit 4600e detects a failure of any router, the participation / leaving message distribution unit 4400e updates a route distribution rule that is defined to perform distribution to the router, Then, the participation message generation unit 4700e is instructed to transmit the participation message to the newly assigned router.

  In this way, when a failure is detected, the route distribution rule is updated, and the participation message that has been distributed to the router that has detected the failure is distributed to another router, thereby realizing redundancy for the failure. Further, the participation message generation unit 4700e transmits the participation message to the newly assigned router, so that the multicast data transfer is resumed early.

  The failure detection unit 4600e monitors the survival confirmation message transmitted from the router. If there is a router that does not transmit the survival confirmation message for a certain period of time, the failure detection unit 4600e determines that a failure has occurred in the router. It is a processing unit that notifies the effect. FIG. 21 is a functional block diagram illustrating a configuration of the failure detection unit 4600e. As shown in the figure, the failure detection unit 4600e has a message disconnection detection unit 4610e and a timer 4620e.

  When the message disconnection detection unit 4610e receives the existence confirmation message, the message disconnection detection unit 4610e starts a timer corresponding to the port that has received the message. If the existence confirmation message is not received at the same port for a certain period of time and the timer times out, it is determined that a failure has occurred in the router connected to the port, and the determination is made, and the join / leave message distribution unit 4400e. Notification to.

  The participation message generation unit 4700e is a processing unit that generates a participation message to the router designated by the participation / leaving message distribution unit 4400e and requests the packet transfer unit 4500e to transfer the message. The packet transfer unit 4500e is a processing unit that transfers a packet delivered from the packet identification unit 4200e, the participation / leaving message distribution unit 4400e, and the participation message generation unit 4700e via the network interface unit 4100e.

  Next, the processing procedure of the load balancer 4000e will be described. Since the process at the normal time conforms to the first to fourth embodiments, the process procedure at the time of abnormality will be described here. FIG. 22 is a flowchart illustrating a processing procedure when a message disconnection is detected.

  If the failure detection unit 4600e receives a survival confirmation message (step S5001), the failure detection unit 4600e acquires a port that has received the message (step S5002), and starts a timer corresponding to the port (step S5003). If a timeout has occurred without receiving a survival confirmation message at the same port for a certain period of time (Yes at step S5004), the participation / leaving message distribution unit 4400e is notified that a message disconnection has occurred (step S5005).

  The join / leave message distribution unit 4400e that received the notification updates the route distribution rule, and replaces the port in which the message disconnection is detected with another port (step S5101). Then, the participation message generation unit 4700e is instructed to transmit the participation message to the router connected to the port newly set as the distribution destination (step S5102).

  Upon receiving the instruction, the participation message generation unit 4700e generates a participation message for the instructed router (step S5201), and requests the packet transfer unit 4500e to transmit it to the router via the newly set port. (Step S5202).

  As described above, in the fifth embodiment, a processing unit for detecting a router abnormality is added, and when a router abnormality is detected, a distribution rule for which the router is a distribution destination is assigned to another router. Is updated as the distribution destination, so that when a failure occurs in the router, the transfer processing can be taken over by another router, and redundancy is realized.

  In this embodiment, the router failure is detected by monitoring the survival confirmation message. However, the router failure may be detected by monitoring the multicast data. Further, an echo request message such as PING may be periodically transmitted to each router, and a failure may be considered if a response is not obtained within a certain time.

  In the above-described embodiment, it is assumed that all multicast data is handled equally. However, when there is a bandwidth limitation, it may be necessary to preferentially handle specific multicast data. Therefore, in the sixth embodiment, an example in which priority is given to multicast data will be described.

  First, the configuration of the load distribution apparatus according to the present embodiment will be described. FIG. 23 is a functional block diagram illustrating the configuration of the load distribution apparatus according to the present embodiment. As shown in the figure, the load distribution device 4000f includes a network interface unit 4100f, a packet identification unit 4200f, a survival confirmation message discard unit 4300f, a join / leave message distribution unit 4400f, a packet transfer unit 4500f, and a leave message. A generating unit 4800f.

  The network interface unit 4100f is an interface unit for exchanging packets through the network. The network interface unit 4100f has a plurality of ports for connecting to the router and a port for connecting to the LAN. Note that a plurality of ports for connecting to the router do not necessarily have to be physically present, and may be virtually divided into a plurality of ports by a VLAN or the like.

  The packet identification unit 4200f is a processing unit that identifies the type of packet received by the network interface unit 4100f and delivers it to the processing unit according to the type. Specifically, if the received packet is a survival confirmation message, it is delivered to the survival confirmation message discarding unit 4300f. If it is a participation message or a withdrawal message, it is delivered to the participation / leaving message sorting unit 4400f. Hand over to part 4500f.

  The survival confirmation message discarding unit 4300f is a treatment unit that discards the survival confirmation message without transferring it. The participation / leaving message sorting unit 4400f is a processing unit that determines which router device is to sort the joining message and the leaving message based on a route sorting rule.

  In addition, when the join / leave message sorting unit 4400f receives a join message of a new multicast address, the number of multicast addresses that have already been transferred exceeds a certain number, and the priority of the new multicast address If the rank is higher than the existing one, the multicast address having the lowest priority is selected from the multicast addresses transferred on the same route, and the leave message generator 4800f is instructed to leave the set multicast address. Send a message. As described above, when the load exceeds a certain standard, the transfer of the multicast data having the low priority is stopped, so that the bandwidth of the multicast data having the high priority can be secured.

  FIG. 24 is a sample diagram showing an example of a route distribution rule. As shown in the figure, the route distribution rule in this embodiment holds a multicast address and an output route of a packet having the multicast address as a pair, and can hold a priority. Yes.

  The leave message generation unit 4800f is a processing unit that generates a leave message to the router instructed by the join / leave message distribution unit 4400f and requests the packet transfer unit 4500f to transfer. The packet transfer unit 4500f is a processing unit that transfers the packet delivered from the packet identification unit 4200f, the join / leave message sorting unit 4400f, and the leave message generation unit 4800f via the network interface unit 4100f.

  As described above, in the sixth embodiment, when the load exceeds a certain standard, the transfer of multicast data with a low priority is stopped, so a bandwidth for multicast data with a high priority is secured. can do.

(Appendix 1) A load balancer connected to a plurality of routers that perform multicast data transfer processing,
A packet identification means for identifying the type of the received packet;
And a message distribution unit that exclusively distributes the packet identified by the packet identification unit as a participation message or a leaving message to a router based on a distribution rule stored in the storage unit.

(Supplementary note 2) The load distribution apparatus according to supplementary note 1, further comprising a survival confirmation message discarding unit that discards the packet identified by the packet identification unit as a survival confirmation message.

(Supplementary note 3) The load distribution apparatus according to Supplementary note 1 or 2, wherein the message distribution unit dynamically adds the distribution rule in consideration of equalizing the load on the router.

(Supplementary Note 4) The message distribution means calculates the multicast address included in the participation message or the leave message, and acquires the distribution destination information from the distribution rule using a value converted into a predetermined range of numerical values. The load distribution apparatus according to appendix 1 or 2, characterized by:

(Additional remark 5) The said message distribution means acquires the information of a distribution destination from the said distribution rule using the IP address of the transmission source of the multicast data contained in a participation message or a leaving message as a clue. The load balancer described in 1.

(Additional remark 6) It further has the failure detection means which detects the failure of a router,
If the failure detection unit detects a router failure, the message distribution unit updates a distribution rule that uses the router as a distribution destination, and replaces the distribution destination with another router. The load balancer described in 1.

(Appendix 7) Participation message generation for generating a participation message for a router as a new distribution destination when the failure detection unit detects a failure of the router and the message distribution unit replaces the distribution destination The load distribution apparatus according to appendix 6, further comprising means.

(Additional remark 8) The said load detection means detects the failure of a router by monitoring the survival confirmation message transmitted from a router, The load distribution apparatus of Additional remark 6 or 7 characterized by the above-mentioned.

(Supplementary note 9) The load distribution apparatus according to supplementary note 6 or 7, wherein the failure detection means detects a failure of the router by monitoring multicast data transmitted from the router.

(Supplementary note 10) The supplementary note 6 or 7, wherein the failure detection means periodically transmits a message for requesting a response to the router and considers that a failure has occurred in the router when there is no response for a predetermined period The load balancer described in 1.

(Supplementary Note 11) When the load on the router exceeds a predetermined threshold, the message distribution unit refers to the priority order of each multicast address stored in the storage unit, and transfers the data of the multicast address having the lowest priority order. The load balancer according to appendix 1 or 2, wherein the router is instructed to cancel the process.

(Supplementary note 12) A load distribution method for controlling a plurality of routers that perform multicast data transfer processing,
A packet identification step for identifying the type of the received packet;
A message distribution step, wherein the packet identification step includes a message distribution step that distributes the packet identified as the join message or the leave message exclusively to the router based on a distribution rule stored in the storage means.

  As described above, the load distribution apparatus and the load distribution method according to the present invention are useful for load distribution of multicast data transfer processing, and in particular, realize load distribution of multicast data transfer processing without imposing a burden on the router. However, it is suitable when it is necessary to perform a high-speed transfer start operation.

It is explanatory drawing for demonstrating the principle of the load distribution system which concerns on a present Example. It is a functional block diagram which shows the structure of the load distribution apparatus which concerns on a present Example. It is a functional block diagram which shows the structure of a packet identification part. It is a sample figure which shows an example of an identification rule. It is a functional block diagram which shows the structure of a joining / leaving message distribution part. It is a sample figure which shows an example of a route distribution rule. It is a flowchart which shows the process sequence of the load distribution apparatus shown in FIG. It is a flowchart which shows the process sequence of a transfer destination determination process. It is a functional block diagram which shows the structure of a joining / leaving message distribution part. It is a sample figure which shows an example of a route distribution rule. It is a flowchart which shows the process sequence of a transfer destination determination process. It is a functional block diagram which shows the structure of a joining / leaving message distribution part. It is a sample figure which shows an example of a route distribution rule. It is a sample figure which shows an example of the number-of-entry entry number information. It is a flowchart which shows the process sequence of a transfer destination determination process. It is a flowchart which shows the process sequence of a transfer destination determination process. It is a functional block diagram which shows the structure of a joining / leaving message distribution part. It is a sample figure which shows an example of a route distribution rule. It is a flowchart which shows the process sequence of a transfer destination determination process. It is a functional block diagram which shows the structure of the load distribution apparatus which concerns on a present Example. It is a functional block diagram which shows the structure of a failure detection part. It is a flowchart which shows the process sequence when a message disconnection is detected. It is a functional block diagram which shows the structure of the load distribution apparatus which concerns on a present Example. It is a sample figure which shows an example of a route distribution rule. It is a sample figure which shows an example of the network structure in the case of performing a multicast. It is a sequence diagram which shows the communication procedure in the case of performing a multicast. It is explanatory drawing for demonstrating operation | movement when there exist multiple routers.

Explanation of symbols

100 Internet 200 LAN
1000 Server 2001, 2002, 2003 Router 3001, 3002, 3003 Terminal 4000, 4000a, 4000e Load balancer 4100a, 4100e, 4100f Network interface unit 4200a, 4200e, 4200f Packet identification unit 4210a Header extraction unit 4220a Identification rule retrieval unit 4230a Identification rule Storage unit 4300a, 4300e, 4300f Survival confirmation message discard unit 4400a, 4400b, 4400c, 4400e, 4400f Join / leave message distribution unit 4410a, 4410b, 4410c Header extraction unit 4410d Source address extraction unit 4420a, 4420b, 4420d Route distribution rule Search unit 4421c Join message processing unit 4422c Leave message processing unit 442 3c Timers 4430a, 4430b, 4430c, 4430d Route allocation rule storage unit 4431c Route entry count storage unit 4440b Header information calculation unit 4450c Type determination unit 4500a, 4500e, 4500f Packet transfer unit 4600e Failure detection unit 4610e Message disconnection detection unit 4620e Timer 4700e Join message generator 4800f Leave message generator

Claims (4)

A load balancer connected between a plurality of routers and terminal devices that perform multicast data transfer processing,
A packet identification means for identifying the type of the received packet;
The packet identifying means stores in the storage means a packet that identifies the type of packet received from the terminal device as a join message or a leave message multicast to the router with the multicast address received by the terminal device itself as the destination. A message distribution unit that distributes exclusively to the router based on the distributed distribution rule ;
The packet identification means discards the packet identified as the existence confirmation message multicasted from the plurality of routers, the type of received packet, and the existence confirmation message discarding means,
A load balancer comprising:   The load distribution apparatus according to claim 1, wherein the message distribution unit dynamically adds the distribution rule in consideration of equalizing router loads. It further comprises a failure detection means for detecting a router failure,
The message distribution unit, when the failure detecting means detects failure of the router, to claim 1, to update the sorting rule that the target allocation for the router, and replaces the assignment destination to other routers The load balancer described. A load balancing method for controlling a plurality of routers and terminal devices that perform multicast data transfer processing,
A packet identification step for identifying the type of the received packet;
The packet identifying step stores in the storage means a packet that identifies the type of packet received from the terminal device as a join message or a leave message that is multicast to the router with the multicast address received by the terminal device itself as the destination. A message distribution step that distributes exclusively to the router based on the distributed distribution rule ;
The packet identification step discards the packet identified as the type of the received packet and the survival confirmation message multicast from the plurality of routers, and
A load balancing method comprising:

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